(a) Field of the Invention
The present invention relates to a signal inspection system for a rotation control device and a method thereof, and more particularly to a signal inspection technique that transforms signals into a machine language and then deciphers the signals.
(b) Description of the Prior Art
It is known that an electronic device has a key group for controlling direction keys. When the key group is in use, it enables a user to switch various functions or select options on the window of the electronic device and thereby permits the user to operate various functions on the window of the electronic device with ease.
The above-mentioned key group consists of four direction keys (up, down, left, and right). After the up, down, left, or right direction key is pressed, the cursor can be controlled to move in the up, down, left, or right direction, meanwhile, which permits a user to see that the cursor is switched from a previous item to a next item on the display so that the user can switch various functions. After the user has selected an option and presses a confirmation key to perform the confirmation action, the function selection has been made. While these four direction keys can permit a user to switch various functions or select options on the display, such operation causes the user great inconvenience and further increases the operational complexity. This often makes it difficult to control the action of the options on the window.
Therefore, some researchers further proposed a switch structure having a three-way operation knob which is rotated or pressed by a user to permit the user to switch various function options on the window.
When a program is used for inspecting such three-way operation knob, the outputs of two signals A, B are generally used for deciding whether the three-way operation knob is rotated in a clockwise direction or in a counterclockwise direction. The decision is based on the output waveforms of the two signals A, B. In general, it is first decided that signal A is at a logical high level, and then it is decided whether the level of signal B is rising or falling. If the level of signal B is rising, it is decided that the three-way operation knob is rotated in a clockwise direction; if the level of signal B is falling, it is decided that the three-way operation knob is rotated in a counterclockwise direction. However, the crosstalk may be induced by the changes in signal edges (rising and falling edges) to a very great extent under the condition that the changes in signal edges are used for making the decision. The more rapidly signal edges change, the greater the crosstalk may be induced. For example, when the decision is continuously made during rising and falling, the response time might be insufficient. Consequently, it has been found that the crosstalk easily leads to faulty decisions during executing an inspection program such leading to poor accuracy of the inspection result.
As a result of a variety of extensive and intensive studies and discussions to improve the influence of faulty decisions due to changes in signal edges on the inspection result as addressed above, the inventors herein propose a signal inspection system for a rotation control device and a method thereof based on their research for many years and plenty of practical experience, thereby accomplishing the foregoing expectations.